Synthesis of PdRu/C electrocatalysts prepared with sodium borohydride reduction method for ethanol and glycerol electro oxidation in alkaline media

The PdRu/C electrocatalysts were synthesized by the sodium borohydride reduction method, with 20% of the metallic load. The metal nanoparticles were supported on Carbo Vulcan XC-72, loading to different Pd:Ru mass proportions. The electrocatalysts obtained in this work were characterized by X-ray dispersive energy spectroscopy (EDX), X-ray diffraction (DRX), transmission electron microscopy (TEM), X-ray excited photoelectron spectroscopy (XPS), Fourier- transform infrared spectroscopy (ATR-FTIR), cyclic voltammetry and chronoamperometry. It also applied to direct-ethanol and glycerol fuel cells (DEFC and DGFC). The characterization by EDX allowed to obtain information about the respect of the atomic composition of the material under study. XRD spectra for all PdRu / C electrocatalysts indicate a shift from the Pd peak (fcc) relative to the plane (220) to higher 2θ values. Histograms achieved by counting nanoparticles recorded by TEM for PdRu/C showing homogeneous nanoparticles and distributed on the support with sizes between 2.9 and 6.5 nm. The XPS results revealed different oxidation states (Ru0 and RuO₂) in which they favor oxidation of adsorbed intermediate species, through the bifunctional mechanism. The PdRu/C electrocatalyst (90:10) demonstrated the best performance for the electrocatalytic oxidation of ethanol and glycerol, observing the analyzes of linear voltammetry and chronoamperometry, however, in the tests using direct-ethanol and glycerol fuel (DEFC and DGFC) PdRu/C (70:30) electrocatalyst exhibited the highest power density value compared to other electrocatalysts. (author)